The necessary condition for the reduction of body mass is a negative energy balance. Energy intake must be consistently lower than energy expenditure in order for weight loss to occur. Therefore, any weight control strategy must address one or both parts of the energy equation; intake or expenditure. With regard to the control of energy intake, two broad strategies can be adopted: the enhancement of the satiety response to food or the blockade of absorption. The physical and chemical properties of various foods can be used to achieve both effects.
With specific regard to the modulation of appetite, those processes responsible for the termination of a meal and the suppression of subsequent intake are of particular interest. The within meal processes of satiation and the post-meal end state of satiety are generated by the sensory, physical and chemical characteristics of the food consumed. The strength of these signals determines meal duration and meal size, and the length of the post-meal interval before the next eating occasion. The activation of such signals can be employed to enhance the appetite response to food and limit caloric intake.
Various naturally occurring ingredients including herbal extracts have been shown to produce beneficial effects on appetite and weight control when used as supplements or food components (Ruxton, et al. (2005) Br. Food J. 107:111-125; Ruxton, et al. (2007) Br. Food J. 109: 416-428). ZOTRIM is a mixed herbal preparation containing Yerbe Maté, Guarana and Damiana, common ingredients of commercially available drinks, and the product is available in the UK as a food supplement. This herb extract formulation significantly delays gastric emptying, reduced the time to perceived gastric fullness and induced significant weight loss over 45 days in overweight patients (Anderson & Fogh (2001) J. Hum. Nutr. Dietet. 14:243-250). A consumer study has also been undertaken to test the efficacy of this preparation in the field. A total of 48 free-living subjects completed a 28-day trial and demonstrated a self-reported mean weight loss of 2.3 kg. Questionnaire data suggested that subjects ate less at meals and snacked less frequently (Ruxton (2004) Nutr. Food Sci. 34:25-28; Ruxton, et al. (2005) Nut. Food Sci. 35:303-331; Ruxton, et al. (2007) supra). However, the effects of ZOTRIM on human food intake, feeding behaviour and subjective feelings of appetite and satiety were not determined.
FIBRESURE is a 100% natural fiber supplement that can be taken daily. The term fiber covers a wide variety of substances belonging to the family of carbohydrates that resist hydrolysis by human alimentary enzymes but are fermented by colonic micro flora (Bianchi & Capurso (2002) Dig. Liver Dis. 34(Suppl 2):S129-33). Fiber is normally connected with increases in satiety due to its high viscosity and bulking effect (Burton-Freeman (2000) J. Nutr. 130:272 S-275S). However, FIBRESURE is a fiber product with little effect on viscosity. Current recommendations for the management of obesity and diabetes mellitus include an increase in dietary fiber intake, as it may contribute to lower fasting and postprandial plasma glucose concentrations and improvement of glycaemic control, which can help control energy intake (Vinik & Jenkins (1988) Diabetes Care 11:160-173). FIBRESURE contains the soluble fiber inulin, which is a prebiotic carbohydrate derived from chicory root. Inulin and inulin-type fructans are mostly oligosaccharides or oligofructoses and stimulate colonic production of Short Chain Fatty Acids (SCFAs), (Guarner (2005) Brit. J. Nutr. 93:S61-5). Fiber fermentability which produces SCFA has been linked with increasing satiety (Bosch (2008) Br. J. Nutr. 102:318-325).
The mechanism by which inulin and inulin-type fructans exert a satiating effect has not been identified. There are many gastrointestinal peptides that affect food intake such as ghrelin, cholecystokinin (CCK), glucagon-like peptide-1 (7-36) amide (GLP-1), oxyntomodulin, peptide YY (PYY) and pancreatic polypeptide (PP). Fructans modulate gastrointestinal peptides involved in the control of food intake, particularly GLP-1 and ghrelin (Orskov, et al. (1989) J. Biol. Chem. 264(22):12826-12829). GLP-1 is an anorectic peptide secreted by the L-cells which suppresses meal-induced gastric acid and pancreatic juice secretion and slows gastric emptying (Schjoldager, et al. (1989) Dig. Dis. Sci. 34:703-708). There are several studies showing that peripheral injection of GLP-1 decreases food intake and consequently body weight in rats and human subjects, (Meier, et al. (2002) Eur. J. Pharmacol. 440:269-279; Zander, et al. (2002) Lancet 359:824-830). Ghrelin is associated with the mesolimbic cholinergic dopaminergic reward system. This reward link is composed of cholinergic input from the laterodorsal tegmental area to the mesolimbic dopamine system that originates in the ventral tegmental area and projects to the nucleus accumbens (Jerlhag, et al. (2007) Addict. Biol. 12(1):6-16). In this respect, treatment of human volunteers with approximately 20 g of oligofructose per day for 7 days increased serum GLP-1 levels (Piche, et al. (2003) Gastroenterology 124(4):894-902). Furthermore, in a study of 14 healthy volunteers, it was found that the gut peptide GLP-1 decreases motility in the antro-duodeno-jejunal region thus inducing satiety (Helistrom, et al. (2008) Neurogastroenterol. Motil. 20(6):649-59).